Fuel pump



A. M. BABITCH June 2, 1953 .FUEL PUMP 2 Sheets-Sheet `l Filed Jan. 10,1948 /'lISn/ventor y? 'attorney A. M.' BBITCH FUEL PUMP June 2, 1953 2sheets-sheet 2 Filed Jan; 10., 1948 Patented June 2, 1953 FUEL PUMPAbraham M. Babitch, Flint, Mich., assignerl to General MotorsCorporation, Detroit, Mich., a

corporation of Delaware Application January 10, 1948, Serial No. 1,511

(Cl. S-38) 16 Claims.

The present invention relates to pumps and more particularly tooperating mechanisms for pumps of the diaphragm type.

Diaphragm pumps are used extensively in automotive vehicles fortransferring fuel from a reservoir to the engine. Such pumps usuallyemploy an operating mechanism adapted to actuate the diaphragm against abiasing spring during the suction stroke and utilize the biasing springto actuate the diaphragm during the discharge stroke. A mechanismcommonly employed in cooperation with such a biasing spring comprises alever which is continuously held in contact with a driving cam withinthe engine casing and some form of linkage between the diaphragm andlever which permits the diaphragm to have a variable discharge stroke inaccordance with the pressure in the fuel delivery line. As the powerrequired to actuate this type of mechanism varies considerably over acomplete cycle of diaphragm movement due to the action of the biasingspring in resisting the suction stroke and assisting the dischargestroke such `a mechanism is not particularly suitable to operation bysmall motors adapted to function in the low voltage electrical system ofan automotive vehicle. In these instances where it is desirable toactuate the pumps by an electrical motor adapted to function in the lowvoltage circuit of an automotive vehicle, as for example, in locatingthe fuel pump at a point remote from the engine, a diaphragm actuatingmechanism is preferred where the force required to actuate the diaphragmunder conditions where there is very little or no pressure in thepumping chamber, is about equal for both the suction and dischargestrokes and limited to the force required to overcome the friction in.

the moving parts of the mechanism. I

It is therefore an object of this invention to provide a fuel pump withan actuating mechanism adapted to operation by a lightweight, lowstarting torque motor capable of functioning in the low voltageelectrical system of an automotive vehicle.

It is another object of this invention to provide a fuel pump with anoil reservoir which will' insure adequate lubrication of the movingparts of the actuating mechanism.

These and other objects are attained in accordance with o-ne form of theinvention by providing a connecting mechanism between the diaphragm ofthe pump and the actuating motor which is collapsible against the forceof biasingA springs along an axis through thev mechanism connections.The mechanism comprises a cross- 2 Y head connected to a motor operatedeccentric and mounted for limited reciprocation against the force of abiasing spring between parallel legs of a closed frame member. closedwithin a housing with an internal conguration adapted to confine aquantity of lubricating oil for the lubrication of the moving parts ofthe mechanism. I

With this form of mechanism and housing adequate lubrication is providedfor the mechanism and the force required to start the diaphragmreciprocating or pumping where there is very little or no pressure inthe pumping chamber is the force required Ato overcome the friction ofthe moving parts of the mechanism.

The novel features which are characteristic of the present invention areset forth with particularity in the appended claims. The inventionitself, however, will be best understood by reference to the' followingspecification when considered in connection with the accompanyingdrawings in which Figure 1 is a side view of the fuel pump partly insection and partly broken away, embodying one form of the presentinvention; Figure 2 is an end View of the mechanism and mechanismhousing taken substantially along the line 2-'2 of Figure 1 andillustrating the relative position of the mechanism parts when themechanism is pumping;A Figure 3 is a side view similar to Figure 2illustrating the relative position of the mechanism parts when the pumpis idling; Figure 4 is an exploded perspective View of the .relativelyslidable mechanism parts illustrated in Figures 1, 2 and 3; Figure 5 isan end view of theenclosing housing and one modification of themechanismof the present invention and Figure 6 is a side View of themechanism and housing illustrated in Figure 5.

Referring now to the .drawings and more particularly to Figure 1 thereis illustrated a fuel pump having a casing formed of a plurality ofsections and comprising a main body member I, a cap 2, a partitioningmember 3 and a mechanism housing member 4. The main body member I isprovided with threaded inlet and outlet passages 5 and 6 respectivelyand a lateral passage 'I separated from the inlet passage 5"by a pluginsert 8. A receptacle 9 positioned adjacent a'recess 'I0 in the mainbody I provides a collecting chamber II for sediment drawn into thefuelv pump from a reservoir (not shown). The receptacle l9 is held inoperative position by a spring4 clamp I2 and an adjustable thumb screwI3. 'A gasket I4 spaced between the main body mem'- ber I and thereceptacle 9 forms a liquid-tight. seal. Communication is providedbetween the The mechanism is en- Sediment chamber I I and the passagesof the main body member I through ports I5 and i5 formed adjacent theinlet passage 5 and the lateral passage I respectively. A cylindricallter screen I'I positioned adjacent a boss i3 extending downwardly fromthe main body member I forms a barrier to the passage of sediment intothe lateral passage '1. The lter screen Il is held in position by ascrew-threaded member I9.

Pulsator chambers and 2l communicating with the inlet and outletpassages 5 and 5 respectively, are provided by forming the main bodymember l with an integral section 22 and spacing a liexible diaphragm23-of suitable material between the main body member I and cap 2.

A disk-shaped member 24 is positioned in a recess 25 in the main bodymember and cooperates with the integral section to form valve controlledcommunicating passages between the pumping chamber 28 and the inlet andoutlet passages of the pump. The disk-shaped member is held in itsposition of cooperation against a gasket 2t by a screw-threaded member2.

The pumping chamber 28 is formed with a movable wall comprising aiiexible diaphragm 29 ofsuitable material clamped about its peripheraledge between the mainbody member l and the partitioning member 3. Toprovide means for actuating the diaphragm 29 it is connected to anoperating stem 32 slidably mounted in a bushing member 33 positioned ina central bore in the partitioning member 3. The stem 32 and diaphragm29 are assembled int'o a unitary structure by forming the stem 32 withone end 3l oi smaller diameter than the main body of the stem andinserting the end 3| in a central hole 39 in the diaphragm. Disk-shapedmembers 34 and 35 are spaced on opposite sides of the diaphragm and theassembly is secured by peening the end 3 to secure a washer 36 having acentral aperture slightly larger than the end 3l. With the dish-shapedmembers arranged as above inen- `tioned, the flexible portion of thediaphragm is limited to the area between the peripheral edges of thedisks and the inner edges of vthe casini,r members I and 3.

Valve controlling means for the pumping chamber are provided by a pairof one-Way valves inversely arranged to provide liquid flow in onedirection to and from the pumping chamber. rIhe valve controllingmeanscomprise a Vpair of disks 3'! normally held in contact with thelvalve seats of inserts 38v by springs 39. Passages 40 and fil areprovided in the disk member 24 and integral section 22 respectively forcommunication between the pumping chamber 23 and the inlet and outletpassages 5 and` 6.

Actuation of the diaphragm 29 is obtained by a low voltage, low startingtorque, electric, motor 42 having its shaft 43` formed with an.eccentric portion 44. The motion of the rotating eccentric portion 44 istransferred tothe diaphragm stem 32 through a lost motion mechanism, oneform being illustrated in detail in Figs. 2, 3 and 4, and a modiiicationthereof being illustrated in Figs. 5 and 6.

The lost motion mechanism of Figs. 2'. 3 and 4 comprises a bifurcatedmember` 45 pivotally connected to the diaphragm stem 32 through a member46 xedly attached to the arms of the bifurcated member 45. A cross head4'!V provided with slots 48 and 49 is slidably mounted on the bifurcatedmember 45 and pivotally connected through a link 50. to the eccentricportion 44 of motor shaft 43. The crosshead 41 is normally biaseddownwardly on the bifurcated member 45 by helical spring members 5Imounted on the arms. An oblong slot 52 in a projecting arm 53 on thebifurcated member 45 cooperates with a pin 54 connecting the link 5i)with the crosshead 41 to limit the relative slidability of the crossmember 4l. An arm 55 projecting downwardly from the bifurcated member 45and recessed in a well 56 in the mechanism housing 4 provides a guidefor the reciprocating motion of the biiurcated member 45.

The lower portion of the lost motion mechanism housing 4 is formed tocontain a supply of lubricating'material for the lost motion mechanism.The parts are lubricated by immersion of the lower portion of themechanism in the lubricant and the motion of the mechanism when inoperation. To provide against the loss of the lubricant, gaskets 51 and5S form liquid-tight seals where the mechanism housing 4 and thepartitioning member 3 and motor housing yare joined. To insureagainstloss of the lubricant irrespective of the position of the fuel pump,:the boss 59 projecting downwardly from the partitioning member 3 isprovided. The boss forms a wall or barrier against loss of lubricantthrough the space between the stem 32 and the bushing 33; it beingadapted to conne a predetermined quantity of lubricant in the wellformed by the boss, the wall of the partitioning member 3 and mechanismhousing 4 when the pump is in an inverted position.

In operation the inverse arrangement of the valves provides for liquidflow in one direction only through the pumping chamber. On thedownstroke of the diaphragm 29, a vacuum is created in the pumpingchamber which causes fuel to be drawn from the reservoir (not shown)through the inlet passages of the pump to the pumping chamber. When themovement of the diaphragm is reversed the fuel is forced from thepumping chamber to the engine carburetor (not shown). As the iioat valveof the carburetor controls the admission of fuel to the carburetor andthe supply of fuel is at times greater than the demand of the engine,pressure is built up in the pumping chamber exerting a force on thediaphragm tending to restrict its movement. When this force becomesgreater than the force exerted by biasing springs 5I on thereciprocating member 4'1, the reciprocating member slides on theconnecting rod or bifurcated member 45 and the fuel flow from the pumpis reduced. With the pressure in the pumping chamber at a maximum thereciprocating member reciprocates on the connecting rod through a strokeequal to the throw of the eccentric on the motor shaft and the diaphragmremains idle. Likewise v as the pressure in the pumping chamber isreduced the force exerted by the biasing springs on the reciprocatingmember gradually overcomes that exerted on the diaphragm and thediaphragm movement becomes equal to the throw of the eccentric.

In the modification illustratedv in Figs. 5 and 6, the mechanismcomprises an oblong 01 closed frame member 58 pivotally connected at themidpoint of its upper crossarm to the diaphragm stem 32 and a crosshead6i slidably mounted between the legs of the frame and connected througha depending projection to the lower crossarm oi the frame. The crosshead6l is provided with a circular aperture 62 which isI adapted to receivefor rotation therein an eccentric 63 tted to the end of the motor shaft43. The depending projection is provided witha slotted recess 64adapting it to slidably receive the lower crossarm of the frame member60. An oblong slot 65 provided in the lower crossarm of the framepermits limited reciprocation of the crosshead 6i in the frame member 60while a biasing spring 66 resists reciprocation of the crosshead andnormally forces the crosshead downwardly to the limit of its travel onthe frame. To insure lubrication of the eccentric 63 an oil hole isprovided in the top of the crosshead.

From the description of the modificationit will be clear that theoperation of the cooperating parts will be the same as that describedhereinabove in connection with the mechanism illustrated in Figs. 2, 3and 4; both providing a variable stroke to the diaphragm determined bythe pressure in the pumping chamber.

With these forms of mechanism it will-be obvious that on starting thepump with little or no pressure in the pumping chamber the only forcerequired of the actuating motor isthat required to overcome the frictionin the moving parts. A pump with such a mechanism is suited to operationby small direct current motors of low starting torque characteristicssuch as those adapted to operation in the low voltage electrical systemof automotive vehicles. Furthermore, such motors would not be stalledwhen the pressure is built up in the pumping chamber as the torquecharacteristic increases with increases in the running speed.

A fuel pump with an actuating mechanism such as hereinabove describedwill nd particularly useful application in automotive vehicles andaircraft where it is preferred to locate the pumps in positions remotefrom the engine. Such a pump has the additional advantage in that itsactuating source may be small, light in weight and characterized by lowpower requirements.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a fuel pump, a pumping chamber in which the pressure Varies, aflexible diaphragm forming one wall of said pumping chamber affected bysaid pressure, a low starting torque electric rotary driving motorhaving an eccentric for actuating said diaphragm and a mechanismoperatively connecting said diaphragm and said eccentric for imparting avariable stroke to said diaphragm determined by the pressure on thediaphragm, said mechanism comprising relatively movable members, oneforming a guide member for the other and linearly movable with respectto the other, said members being attached respectively to said diaphragmand said eccentric and a spring positioned between said members foryieldingly urging one of said members to an extreme position on theother of said members.

2. In a fuel pump, a pumping chamber, a flexible diaphragm forming onewall of said pumping chamber, a low starting torque electric rotarydriving motor having an eccentric for actuating said diaphragm and amechanism operatively connecting said diaphragm and said eccentric forimparting a variable stroke to said diaphragm, said mechanism comprisinga bifurcated guide member and a member attached thereto and slidablethereon and a spring interposed between said members for yieldinglyurging said slidable memberto an extreme position movable diaphragmforming one wall of said pumping chamber, a llow starting torque rotarydriving motor having an eccentric shaft for actuating said diaphragm anda mechanism operatively connecting said diaphragm andy said eccentricshaft for imparting a variable stroke to said diaphragm, said mechanismcomprising a bifurcated member operatively connected to said diaphragm,a member attached to and slidable on said bifurcated member andoperativelyattached to said shaft and springs interposed between saidmembers to yieldingly urge said slidable member to an extreme positionon said bifurcated member, said members being responsive topredetermined pressures on said diaphragm to overcome the pressure ofsaid springs and vary the relative positions of said members withrespect to each other to provide variable stroke diaphragm operation.

4. In a fuel pump, a casing constructed to form a pumping chamber and amechanism housing, a movable diaphragm forming one wall of said pumpingchamber and having a stem projecting into said mechanism housing, apartition member having a centrally located boss extending into saidmechanism housing for slidably mounting said stem, said boss beingadapted in cooperation with said partition member and said mechanismhousing to confine a predetermined amount of lubricant in said mechanismhousing, a rotary driving member having an eccentric shaft for actuatingsaid diaphragm and a mechanism operatively connecting said stem and saideccentric shaft for imparting a variable stroke to said diaphragm, saidmechanism comprising a bifurcated member operatively connected to saidstem, a crosshead attached to and slidable on said bifurcated member andoperatively attached to said eccentric shaft, and springs positionedbetween said bifurcated member and said crosshead to yieldingly urgesaid crosshead to an eX- treme position on said bifurcated member saidbifurcated member and crosshead being responsive to pressures on saiddiaphragm to overcome the pressure of said springs and vary the relativeposition of said crosshead and said bifurcated member with respect toeach other and provide variable stroke operation for said diaphragm.

5. In a pump, a pumping chamber, a reciproeating member forming one wallof said pumping chamber, a low starting torque, electric actuator forsaid reciprocating member and a mechanism operatively connecting saidactuator and said reciprocating member, said mechanism comprising aclosed frame member and a crosshead attached to and slidably mountedwithin said frame member and a spring positioned between said framemember and said crosshead to yieldingly urge said crosshead to anextreme position on said frame member, said member; said frame memberand said crosshead being attached to said reciprocating member and saidactuator respectively.

6. In a fuel pump, a casing constructedV to form a pumping chamber and amechanism housing,` a movable diaphragmrforming one wall said frame foryieldingly urging said crosshead to an eXtreme position on said frame,said spring means being adapted to yield in response to predeterminedpressures in said pump to vary the stroke of said driven means.

13. In a fuel pump having driven means upon which the pressure varies, alow starting torque electric driving motor having an eccentric forimparting reciprocatory motion to said driven means and a mechanismoperatively connecting said driven member and said eccentric fortransferring the rotary motion of said motor into reciprocatory motionof said driven member, said mechanism comprising relatively movableattached members, one of said attached members being connected to saideccentric and the other to said driven member and spring meanspositioned between said relatively movable members for yieldingly urgingsaid relatively movable members in spaced apart relation whilepermitting a foreshortening of the distance between said members againstthe pressure of said spring means to simultaneously vary the stroke ofsaid driven member in response to variations in pressure of said pump.

14. In a fuel pump having driven means, an actuator for impartingreciprocatory motion to said driven means, and a lost motion mechanismconnecting said actuator and driven means for permitting variable strokeoperation of said driven means, said mechanism comprising a closed framemember having spaced leg portions, said frame member being connected tosaid driven member, a crosshead slidably attached to said frame memberand to said actuator, said crosshead having sp-aced slots therein forreceiving said spaced leg portions and spring means posi tioned betweensaid frame member and said cross member for yieldingly urging saidcrosshead to an extreme position on said frame member, said said springmeans being adapted to yield in response to predetermined pressures onsaid driven means to vary the stroke thereof.

15. In a fuel .pump having a, driven means, a rotary actuator having aneccentric for imparting reciprocatory motion to said driven means and a,lost motion mechanism connecting said eccentric and said driven meansfor permitting variable stroke operation of said driven means, saidmechanism comprising a closed frame member connected to said drivenmember and having spaced parallel leg portions, a crosshead slidablyattached to said frame and to said eccentric, said crosshead havingspaced slots therein for receiving said leg portions and guiding themove ments of said crosshead cn said frame, a link attached to saidcrosshead for movement therewith, said link having an aperture thereinfor receiving said eccentric and positively connecting said eccentricand said mechanismJ and spring means positioned between said crossheadand said frame member for yieldingly urging said crosshead to an extremeposition on said frame member, said spring means being adapted tc yieldin response to predetermined pressures on said driven means to vary thestroke thereof.

16. In a fuel pump having driven means, a rotary actuator having aneccentric for imparting reciprocatory motion tor said driven member, anda lost motion mechanism connecting said eccentric and driven means forpermitting variable stroke operation of said driven means, saidmechanism comprising a closed frame member connected to said d :ivenmember and having spaced parallel leg portions, a crosshead slidahlymounted on said frame with portions engaging said leg portions, saidcrosshead having apertures therein journalling said eccentric, meansconnecting said crosshead to said frame to permit limited relativemovement therein and spring means positioned between said frame memberand said crosshead for yieldingly urging said crosshead to an extremeposition on said frame, said spring means being adapted to yield inresponse to predetermined pressures on said driven means to vary thestroke thereof.

ABRAHAM M. BABITCH.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 862,867 Eggleston Aug. 6, 1907 1,327,272 Dellgren Jan. 6, 19201,599,899 Kettering Sept. 14, 1926 1,738,786 McKinley Dec. 10, 19291,749,367 Zubaty Mar. 4, 1930 1,824,467 Darby Sept. 22, 1931 1,946,590Rockwell Feb. 13, 1934 2,308,041 Babitch Jan. 12, 1943

